This invention relates to an articulated arm for conducting the beam from a laser to a point of utilization which moves relative to the laser. The invention relates to the general organization and arrangement of the laser arm and to certain components thereof including joints, mirrors and focusing clamp.
Certain types of lasers, CO.sub.2 lasers for example, are utilized for industrial purposes such as machining, joining, cutting, etc. In general, industrial applications of lasers involve relative motion between the laser beam and a workpiece. Lasers of the industrial type are generally quite massive, and therefore it is generally undesirable to bodily move such a laser with respect to a workpiece.
One alternative procedure involves moving the workpieces in relation to the laser beam but this can be difficult if the workpieces themselves are massive or not conveniently grippable for movement.
Another alternative for effecting relative movement between a laser beam and a workpiece comprises a system of mirrors in which the mirrors are operated by various controls so as to deflect the laser beam in proper fashion onto the workpiece. For example, a common technique is to have an oscillating, or rocking, mirror powered by a servo motor which sweeps a workpiece with laser beam pulses being synchronized with the operation of the mirror so that they are correctly directed onto the workpiece.
It is also very important that the proper distance relationship be maintained so that the laser beam is focussed exactly at the desired point of utilization. Departures from exact focussing yield less than optimal results.
The emergence of industrial robots offers the potential for significant productivity improvements in the manufacture of many articles. The more sophisticated robots are highly versatile, having multiple degrees of freedom (i.e. axes of motion) so as to be capable of operating on workpieces in a number of varied ways. Their dexterity, and the speed and accuracy with which they can be operated, render industrial robots potentially suitable for application to the manufacture of a wide variety of articles requiring cutting, joining, drilling and similar types of operations. Yet industrial laser manufacturing procedures have generally not seemed compatible with industrial robots because of the inherent massiveness of such lasers.
The present invention is directed to an articulated arm which can be used to conduct the laser beam from a laser to a point of utilization which moves in three dimensions relative to the laser. Accordingly the invention is well suited for endowing a robot with a laser operating capability. The robot's speed, dexterity, and accuracy can position the operating point of the articulated laser arm to desired locations thereby avoiding the problems characteristic of prior procedures as described above.
The articulated laser arm of the present invention comprises a number of important aspects. For one, the general organization and arrangement of the laser arm is unique in that it is adapted to passively follow the motion of the robot in a manner which does not impair the speed and accuracy of the robot during its operations on a workpiece. In other words, the articulated laser arm has an organization and arrangement which can follow the complex manipulations of the robot in a manner which imposes negligible loading on the robot.
Another feature of the invention relates to the construction of the joints of the articulated laser arm. The joints are configured in identical assemblies which can be cascaded together with or without intervening tubular sections. The joints are readily interchangeable and allow different geometries to be readily realized depending upon the particular requirements of any given design.
Moreover, each joint comprises a new and unique mirror assembly which reflects the laser beam as it passes through the joint. Each mirror assembly is mounted in such a manner that very precise adjustments can be made to accurately align the incident and reflected laser beam along desired directions of travel through the articulated arm. Furthermore, the mirror assemblies are cooperatively associated with a fluid cooling system with a coolant distributor assembly being used to retain a mirror element within a frame of the mirror assembly. In this way the mirror element is exposed for efficient cooling, yet the construction and arrangement permits the convenient replacement of a mirror element by removal of the coolant distributor assembly.
Still another feature is the focusing clamp which forms the point of utilization of the laser beam. The focusing clamp has opposed jaw elements which are operated onto opposite sides of a workpiece, such as for example onto a seam which is being laser welded. The focusing clamp has an equalizing feature which allows the laser beam to be precisely focused at the point of utilization. Thus, it is not necessary that the workpiece and the robot be precisely relatively positioned since any departures within a certain range from the precise position are taken up by the equalizing feature of the focusing clamp thereby ensuring precise placement of the focussed laser beam at the desired point of utilization.
With the present invention advantages of industrial robots and industrial lasers may be conjointly attained in manufacturing operations with meaningful improvements in productivity, performance, and quality of manufactured products.
The foregoing features, advantages and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.